1. Field of the Invention
Aspects of the present invention relate to a method and apparatus of enhancing a contrast of an input image, and more particularly, to a method and apparatus of enhancing a contrast by increasing a luminance and decreasing the luminance depending on an area of an image.
2. Description of the Related Art
Generally, an image inputted by an image input apparatus has various information of an object, however, an element of a luminance signal is concentrated or distorted by a condition of the image input apparatus, and a characteristic of the object cannot be accurately expressed.
According to a conventional art, a dark image is brightened, and a bright image relatively emphasizes a dark area by variously processing an enhancement gain according to an image after analyzing the image in order to correct the distorted luminance signal.
In this instance, a brightness of the distorted image can be corrected. However, a brightness enhancement of the undistorted image may be omitted, and an original input signal value can be outputted as is. When the above-described conventional art is applied to a movie, a flickering phenomenon can be generated due to a enhancement gain difference between frames of the movie.
Also, according to a conventional art, an average brightness around an input pixel is calculated by using a sliding window or a low pass filter (LPF) in order to enhance a contrast. The peripheral brightness is calculated while the sliding window or a filter continuously overlaps input pixels
In this instance, a window size or a filter size affects an algorithm performance. Because, the larger the window size or the filter size is, the more memory and processing time are needed. Thus, to enhance a image using the window or filter exist many restrictions on operating a real-time application.
Accordingly, a method and apparatus of enhancing a contrast by increasing a luminance and decreasing the luminance depending on an area of an image is needed.